1. Field of the Invention
The invention relates to a sealing structure such as a tube joint, and more particularly to a sealing structure eliminating the necessity of a gasket.
2. Description of the Related Art
In order to keep gastight and/or fluid-tight in apparatuses in which gas and/or fluid run(s) therethrough, various sealing materials have been employed. For instance, when fluid and gaseous materials as well as powder, particles and slurry are to be transferred through a plurality of tubes, those tubes are in general connected with each other through tube joints. One of conventional tube joints is illustrated in FIGS. 1A and 1B. The illustrated conventional tube joint 1 includes a body portion 2 made of metal, and a flange portion 3 formed integrally with the body portion 2 at one end of the body portion 2. The body and flange portions 2 and 3 is formed centrally with a bore 2a. The flange portion 3 has an outer surface 3a at which the tube joint 1 is connected to an opponent tube joint (not illustrated), and is formed with four holes 3b located coaxially with the bore 2a and spaced circumferentially equally to one another.
The tube joint 1 is used as follows. First, the tube joints 1 are welded to tubes at ends thereof. Then, the outer surfaces 3a of two tube joints are made close contact with each other with a gasket sandwiched therebetween. Then, bolts (not illustrated) are inserted into the holes 3b of the two tube joints, and then fastened by nuts to thereby connect the tube joints 1 to each other. Thus, the tubes are made in fluid communication with each other through the tube joints 1.
As mentioned above, the conventional tube joint requires the use of a gasket. However, it takes time and labor to dispose a gasket in position, resulting in reducing efficiency in arranging tubes. In addition, a gasket is in general made of fluorine contained resin to ensure high sealing ability. However, such a gasket is readily deformed or twisted to thereby deteriorate sealing ability of the gasket.
The above mentioned problems are common in apparatuses which need a gasket or packing in order to keep gastight and/or fluid-tight for preventing leakage of gas and/or fluid therefrom.